1. Technical Field
This invention relates to a braking and drive force control apparatus for a vehicle which can perform variable control of the braking and drive force applied to the wheels of the vehicle.
2. Related Art
From in the past, as described in Japanese Patent Application Laid-Open (kokai) No. H 10-210604, for example, an in-wheel motor type vehicle in which a motor is incorporated into each drive wheel is known. The drive force of each drive wheel is individually controlled so that the yaw rate response of the vehicle body to the steering angle sensed by a steering angle sensor matches a target response, and the yawing performance is improved by reflecting rotational movement, sideways movement, slip, and the like of the vehicle body in drive control of each drive wheel.
However, the above-described prior art does not give adequate consideration to upwards and downwards vibration of the vehicle body, i.e., to bouncing of the vehicle body. Bouncing of the vehicle body is usually suppressed by setting the suspension on the hard side, such as by increasing the spring constant of coil springs or by setting the damping force of shock absorbers of the vehicle to a high value. However, suppressing bouncing in this manner results in the problem that the ride comfort becomes poor.
In addition, in the above-described prior art, adequate consideration is not given to variations in the ground contact load of the wheels. In the same manner as described above, variation in the ground contact load of the wheels is suppressed by setting the suspension on the hard side, but again this results in the problem that the ride comfort worsens.